I am having a strange problem lately where my machine will home to a different position. The machine is an Eagle Yang SMV-1000 with a fanuc 0-MD controller.
Every time I home the machine in manual, let's say to inspect a parts, the home postion on the Y axis will shift and controller absolute position gets reset with the new value. If I don't catch it the machine restart and the Y axis is shifted.

I have gone thru the limit switch and even confirmed that the Home limit switch (X17.5) is working well and registering the dog at the same distance every time and it does.

There is something in the reference return steps the machine is doing that I am not understanding. If I try to home the machine several time in a row it will get to a point where the data has shifted too much and after the deceleration it will overshoot and cause an overtravel alarm. I could use some advice!